IntensIve sIlvIculture - Forest Science Labs - Research Network ...

stand data, results were more variable as elements such as B and S showed evidence of being
limiting.
627. Turner, J. and S.J. Mitchell. 2003. The effect of short day treatments on containerized Douglas-fir
morphology, physiology and phenology. New-Forests 26(3): 279-295.
Keywords: nursery operations
growth
tree morphology
tree physiology
photosynthesis
tree phenology
273
Abstract: The effect of short day treatments ('blackout') on Douglas-fir (Pseudotsuga
menziesii (Mirb.) Franco) container seedlings at the time of lift and following cold storage was
investigated. Variables measured included height, root collar diameter (RCD), root growth
capacity (RGC), photosynthetic efficiency after -18 degrees C freezing (PEF), and days to
terminal bud break (DBB). From one to four blackout dormancy induction treatments were
started on three dates (July 12, July 26, and August 10) with 10 or 20 d between multiple
blackouts. Increasing the number of blackout treatments resulted in lower RCD, lower DBB in
the late winter/early spring, and higher PEF in the early fall. Later blackout start dates decreased
PEF in the early fall, and increased overall height and late fall RGC as compared to earlier
blackout start dates. Nurseries growing Douglas-fir seedlings from coastal Pacific Northwest
provenances should be aware that blackout regimes can decrease RGC in the late fall, and cause
quicker dormancy release in the early spring. Coastal Douglas-fir can be lifted and planted in the
early fall, when RGC and DBB are relatively high. If planting between February and April is
necessary, seedlings given blackout should be cold stored in January to maintain an adequate
level of dormancy, RGC and PEF.
628. Vargas-Hernandez, J. and W.T. Adams. 1991. Genetic variation of wood density components in
young coastal Douglas-fir: implications for tree breeding. Canadian-Journal-of-Forest-Research
21(12): 1801-1807.
Keywords: genetic tree improvement
genetic relationships
wood quality
growth
Abstract: A study was made of the genetic control of wood density components (earlywood
density, latewood density, and latewood percentage) and their relationships with overall density
in coastal Douglas fir (Pseudotsuga menziesii var. menziesii) to assess the usefulness of this
information in breeding for wood density. The genetic relationships of wood density with intraring
density variation and bole volume growth were also investigated. Increment cores were taken
at breast height from 15-yr-old trees of 60 open-pollinated families growing in the Coyote Creek
progeny test plantation near Eugene, Oregon, during summer 1988. Averages across each core for
overall wood density, its components and intra-ring density variation were determined by using
X-ray densitometry. Bole volume at age 15 yr for the same trees was derived from tree height and
diameter at breast height measurements taken at the end of the 1987 growing season. Although
wood density components varied significantly among families and were under moderate genetic
control (individual-tree heritability (hisuperscript 2) >0.24), none had a higher heritability than
overall density (hisuperscript 2 = 0.59). Density components had strong genetic correlations with